In thread-joining, great emphasis is laid, nowadays, on good piecers, so that these do not subsequently have to be cleaned out, in an additional operation, by separating out and knotting the thread ends obtained. For this purpose, the otherwise conventional mass threadjoining has often been abandoned (see "Suessen WST Technical Report - SUESSEN - WST CleanCat - SUESSEN - WST SpinCat for the automation of rotor spinning machines", 5.1-03 OOO D 7.79, page 4, paragraph 9, no more "mass thread-joining", or the piecers are replaced by knots immediately following the mass thread-joining (German Offenlegungsschrift No. 2,758,064), this being carried out, in turn, by means of a service device movable along the open-end spinning machine. However, since this service device requires a relatively long time for its work, obtaining high-grade piecers or eliminating poorer piecers has hitherto meant a production loss.
The object of the present invention is to provide a process and a open-end spinning machine which allow uniform thread-joining conditions at the individual spinning units without a production loss.